Make bean paste with yeast. Putting too much salt at first will kill the yeast in the bean paste and affect the yeast fermentation, so the sauce will lose its proper flavor. A is correct;

Natural selection is survival of the fittest and elimination of the unfit. The wolves on the grassland are more and more fierce and good at running, which is the performance of adapting to the environment and the result of long-term natural selection. B wrong;

C, energy flow is one-way flow, gradually decreasing. Generally speaking, only 10% ~ 20% of energy from the last trophic level can flow into the next trophic level, so in an ecosystem, most food chains do not exceed 5 trophic levels, and C is correct;

D, intact fresh fruits are generally wrapped in fresh-keeping bags. In addition to maintaining moisture, the purpose of preservation is achieved by reducing oxygen content and reducing the consumption of organic matter. Therefore, the use of plastic wrap can keep vegetables and fruits fresh, thus prolonging the storage period. The principle of this preservation method is that it can reduce the oxygen concentration and inhibit breathing. Correct.

So choose: B.